Reference is hereby made to other related patent applications which are assigned to the same assignee as the present application; Application of H. Feigenbaum and A. Kaufman entitled "Integral Gas Seal For A fuel Cell Gas Distribution Plate", Ser. No. 430,453, filed on Sept. 30, 1982 and Application of H. Feigenbaum, S. Pudick and R. Singh entitled "Edge Seal For Porous Gas Distribution Plate Of A Fuel Cell", Ser. No. 430,142, filed on Sept. 30, 1982.
The present invention relates to improved elements for use in fuel cells, fuel cells employing such elements, and processes and apparatus for making the elements.
It has been known for some time that fuel cells can be extremely advantageous as power supplies, particularly for certain applications such as a primary source of power in remote areas. It is highly desirable that any such fuel cell assembly be extremely reliable. Various fuel cell systems have been devised in the past to accomplish these purposes. Illustrative of such prior art fuel cells are those shown and described in U.S. Pat. No. 3,709,736, 3,453,149 and 4,175,165. A detailed analysis of fuel cell technology comparing a number of different types of fuel cells appears in the "Energy Technology Handbook" by Douglas M. Consadine, published in 1977 by McGraw Hill Book Company at pages 4-59 to 4-73.
U.S. Patent No. 3,709,736, assigned to the assignee of the present invention, describes a fuel cell system which includes a stacked configuration comprising alternating fuel cell laminates and electrically and thermally conductive impervious cell plates. The laminates include fuel and oxygen electrodes on either side of an electrolyte comprising an immobilized acid. U.S. Pat. No. 3,453,149, assigned to the assignee of this invention, is illustrative of such as immobilized acid electrolyte. In U.S. Pat. No. 4,175,165, assigned to the assignee of the present invention, a stacked array of fuel cells is described wherein gas distribution plates include a plurality of gas flow channels or grooves with the grooves for the hydrogen gas distribution being arranged orthogonally relative to the grooves for the oxygen distribution. The gas distribution plates themselves, whether they are individual termination plates for one or the other of the gases or bi-polar plates for distributing both gases in accordance with this disclosure, are formed of an electrically conductive impervious material.
In more recent designs, the gas distribution plates, which are sometimes called A-plates, are formed of a porous material so that a more uniform and complete flow of gas over the electrode surface is provided. In previous systems where nonporous gas distribution plates were utilized, the reactants always flowed only through the grooves and were contained by the walls thereof. However, in the more recent systems utilized porous plates, it has been necessary to assemble a sealing gasket along the edges of the plate before it was assembled into the cell to prevent the reactant gases from exiting through the plate edges and mixing together. If leakage did occur, the cells could operate improperly or fail altogether.
Accordingly, it is an aim of the present invention to provide an improved process for forming an integral edge seal in a gas distribution plate.
It is a further aim of this invention to provide a process as above wherein the seal layer is formed by impregnating an edge of the plate with a vibratory means.